Patent GB-381171-A (GB)
Title: Improvements in change-over mechanism for cinematograph apparatus
IPC: G03B21/50
Filed: 1931-06-26
Abstract: 381,171. Kinematograph apparatus. STANFORD, J. W., 146, Stockwell Park Road, Brixton, and JEFFERY, W. B. E., 5, Pyrmont Grove, West Norwood, both in London. June 26, 1931, No. 18494. [Class 97 (i).] Change-over mechanism for kinematograph or like apparatus comprises control means having an arm driven at a speed proportional to the speed of one film, and starting means for the driving device of another film operated by the control arm after a predetermined length of the first film has been fed. As shown in Fig. 3, the electric motors 10 .. 13 have controls I .. IV comprising dials 14 .. 17 having control arms 20 .. 23 co-operating with sets of contacts 24 .. 27 and 28, 29. The connection of the motors 10 .. 13 to the supply mains 34, 35 is controlled by relays 30 .. 33 comprising contacts 36, 37, a coil 38, and an armature 39 bridging the contacts 36, 37 and having a movable contact 41 insulated therefrom and coacting with a fixed contact 40. Contacts 36 are connected to the main 35 and to one end of coils 38, while contacts 37 are connected to one side of the motors, the other terminals being connected to the main 34. The other ends of the coils 38 are connected to contacts 41, while contacts 40 are connected to contacts 28. Contacts 25, 27, and 29 are connected to the main 34. Shutter-controls 50 .. 53 comprise coils 55, 56 operating armatures controlling the safety-shutters the common ends of the coils being connected to the main 35 and the other end of coil 56 to contact 26. Selectors 61 .. 64 controlling the order of projection comprise bus-bars 66, 67 connectable by sliders 68, 69 to contacts 70. 71, 72, and 74, 75, 76. Contacts 24 are connected to busbar 67, contacts 26 to bus-bar 66. The second end of coil 55 of shutter-control 50 is connected to contacts 70 of selectors 62, 63, 64, that of coil 55 of control 51 to contact 70 of selector 61 and to contacts 71 of selectors 63, 64, that of coil 55 of control 52 to contact 72 of selector 64 and contacts 71 of selectors 61, 62, and that of coil 55 of control 53 to contact 72 of selectors 61, 62, 63. Contact 41. of relay 30 is connected to contacts 74 of selectors 62, 63, 64, contact 41 of relay 31 to contact 74 of selector 61 and contacts 75 of selectors 63, 64, contact 41 of relay 32 to contacts 75 of selectors 61, 62 and contact 76 of selector 64, and contact 41 of relay 33 to contacts 76 of selectors 61, 62, 63. As shown in Fig. 2, a plate 92 carries reduction gearing 94 driven by a flexible shaft 95 at a speed proportional to the film-feed. The plate 96 carries the contacts 24, .. 27 and 28, 29. A spindle 97 driven by gearing 94 carries one element 98 of a friction clutch, the other element 99 being on a sleeve 100, a knob 101 on which houses in its bore a spring 102 bearing against the sleeve 100 and an abutment 103 on spiidle 97. The sleeve 100 carries both a pointer 106 coacting with a dial 14 comprising two concentric scales graduated in opposite directions and also the control arm 20, movement of which closes the contacts 24, 25 and 26, 27, and opens the contacts 28, 29. The relay 30 after starting the motor 10 remains energized owing to the closing of the holding circuit comprising contacts 40, 41 and 28, 29. Coil 55 of control 50 is energized to maintain the safety shutter of the first projector open, while the other safety - shutters are closed owing to the energization of coils 56 of controls 51, 52, 53. When the pointer 106 of control I approaches the end of the scale 108 the contacts 25, 26 are closed to energize relay 31 and start motor 11. Continued rotation of arm 20 first closes contacts 26, 27 to energize coil 56 of control 50 and coil 55 of control 51 to close the first safety-shutter and open the second, and then opens contacts 28, 29 to break the circuit of relay 30 and stop motor 10. The succeeding projectors are started and stopped in a similar manner. Operations such as striking the arcs and giving warning of the approach of the ends of the films may be similarly controlled. When only two projectors, the first of which is started and stopped manually the arrangements may be simplified by the replacement of the relay 30 of the first projector and the contacts 28, 29 by a switch. The apparatus may also be applied to cameras.